OBSIDIAN SOURCES AND ELEMENTAL ANALYSES OF
ARTIFACTS IN SOUTHERN MESOAMERICA AND
THE NORTHERN INTERMEDIATE AREA
Payson Sheets, Kenneth Hirth, Fred Lange,
Fred Stross, Frank Asaro, and Helen Michel
Obsidian sources, and the proportions of those sources represented in site collections, are known poorly in the
southeast mesoamerican periphery. The Honduran sources of La Esperanza and Giiinope are described and
'fingerprinted" chemically, and their utilization is explored in selected sites in Honduras, Nicaragua, and Costa
Rica. Although prehistoric Nicaraguans and Costa Ricans used obsidian from sources as far away as Honduras
and Guatemala, most of their cutting tools were made from local materials, using informal manufacturing
techniques. The analytical results indicate two sources of new types of obsidian have yet to be found; they may
lie in western Nicaragua.
Losfuentes naturales de obsidiana, y como ellos estan representados en colecci6nes de sitios arqueologicos, no
son bien conocidos al suroeste de Mesoamerica. Datos descriptivos y quimicos de los fuentes hondurenos La
Esperanza y Giiinope son presentados. Tambien, la llegada y uso de la obsidiana de estos fuentes en sitios
arqueologicos en Honduras, Nicaragua, y Costa Rica son considerados. Aunque los indios prehist6ricos de Nicaragua y Costa Rica usaron obsidiana de Honduras y Guatemala, defuentes a larga distancia, hicieron la mayoria
de sus artefactos para cortar de materiales locales, con un tecnico no complicado. Los datos indican que por lo
menos hay dos tipos de obsidiana en la zona con fuentes todavia desconocidos; tal vez queden en el oeste de
Nicaragua.
The major natural sources of obsidian in Mesoamerica, lying in central Mexico and in the Guatemalan highlands, have been analyzed for their major and trace elements, and each has a distinctive
chemical "fingerprint" (e.g., Asaro et al. 1978; Stross et al. 1983). Obsidian artifacts from numerous
mesoamerican sites have been analyzed, and the percentages of the various sources, in different
phases, have contributed important information on resource exploitation and trade networks.
In contrast, obsidian sources in the southeastern periphery of Mesoamerica have been neglected,
and obsidian artifacts from sites in this area and lower Central America have not been analyzed
regularly to determine sources. Here, we describe two sources in southern Honduras and present
the results of analyses of obsidian from selected sites in Honduras, Nicaragua, and Costa Rica.
The Honduran source of La Esperanza has been mentioned in published literature, but not always
accurately. The Giiinope source has not been described before. The data indicate at least two sources
of obsidian have yet to be found in situ; they may lie in western Nicaragua.
OBSIDIAN SOURCES
The La Esperanza
Obsidian Source
The La Esperanza obsidian source is located in the southwestern highlands of Honduras, in the
Department of Intibuca (Figure 1). The source was first reported by Lunardi (1948). About a decade
Payson Sheets, Department of Anthropology, University of Colorado, Boulder CO 80309
Kenneth Hirth, Department of Anthropology, University of Kentucky, Lexington KY 40506
Fred Lange, University of Colorado Museum, University of Colorado, Boulder CO 80309
Fred Stross, Frank Asaro, and Helen Michel, Lawrence Berkeley Laboratory, University of California, 1
Cyclotron Road, Berkeley CA 94720
AmericanAntiquity,55(1), 1990, pp. 144-158.
Copyright? 1990 by the Society for AmericanArchaeology
144
REPORTS
145
Figure 1. Southern Mesoamerica and the Northern Intermediate Area. Inset map, at same scale, identifies
archaeological sites and obsidian sources.
later Plowden examined sites in the La Esperanza area over a period of a few years. He was joined
in 1962 by Bullen, and the two published an article on their findings (Bullen and Plowden 1963),
apparently unaware of Lunardi's work. Although they did not realize there was an obsidian source
at La Esperanza, they did find evidence of occupation and obsidian use extending from the Paleoindian through the Classic periods, and perhaps later. A fluted base of a finely flaked biface,
likely a Clovis point, is evidence of Paleoindian occupation of the area, and probably indicates use
of the La Esperanza obsidian source at that time. The abundant prismatic blades and polychrome
ceramics at various sites in the La Esperanza area indicate source utilization at least during the
Classic period, and likely during the Preclassic and Postclassic periods as well. The "narrow-stemmed
points" Bullen and Plowden (1963:385) attribute to an early ceramic horizon at site Ib-22 are very
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AMERICAN
ANTIQUITY
[Vol. 55, No. 1, 1990]
Figure2. Obsidianlocalesat the La Esperanzaobsidiansource,southwesternHonduras.Roadsare indicated
by darkerlines.
similar to the "pointed stem, ovate blade" bifaces common in western El Salvador, dated to the
Postclassic period (Sheets 1978:23:Figure 2b2-3). They may have erred occasionally in assuming
that some aceramic lithic sites were preceramic. That would lead to an overassignment of collected
materials to the Archaic period, and an underrepresentation of later use and manufacture.
Some of Bullen and Plowden's reasoning errors may have been duplicated by Coe and Flannery
(1964), who surface collected a small locality within the huge El Chayal obsidian outcrop-workshop
complex in Guatemala. Noting the lack of ceramics and prismatic blades, they concluded the industry
probably was aceramic, hence preceramic, and thus either Paleoindian or Archaic. The lack of clear
Paleoindian diagnostic artifacts led them to conclude that the workshop was probably Archaic. The
assumption that the full artifact inventory of a society would be deposited at a specialized quarry
and performing workshop is unwarranted, and the bulk of the artifacts they collected more likely
date to the Late Classic and Postclassic, millennia later than Coe and Flannery suspected (Sheets
1975).
More recently, the Proyecto Arqueol6gico El Cajon continued exploring obsidian exposures and
technology in the La Esperanza area. In 1980 Dennis Coskren and Vito Veliz located and collected
obsidian samples from an outcrop in a road cut near Cerro El Coyote, 2 km west of Quiaterique
(Figure 2, site 7). Chapman (1982) independently reported large quantities of obsidian in the low
hills of El Cedral, 4 km northwest of the town of La Esperanza. A local informant look her to the
area called "Los Hoyos," where she saw evidence of prehistoric subsurface mining of obsidian.
Because of Chapman's (1982) report, the El Cedral area was surveyed by project members in 1983.
Obsidian outcrops, quarry, and mining areas, as well as several production workshops and utilization
areas were identified in the El Cedral region. The survey of the La Esperanza source area is described
more fully by Sorensen and Hirth (1984). Their results are summarized here.
Survey of the El Cedral hills by Hirth and Sorensen identified six sites where obsidian was either
outcropping or was worked (Figure 2). Obsidian nodules ranging from 1 to 30 cm in diameter were
observed over more than a kilometer along a road running along the eastern flank of El Cedral.
Evidently they had washed downslope and were exposed along the road cut and in small quebradas
REPORTS
147
draining the hillside. A local informant indicated that water-worn cobbles can be found in small
drainages around the entire base of El Cedral.
The prehispanic mining area at the summit of El Cedral, known locally as Los Hoyos (Figure 2,
locale 5), first reported by Chapman (1982), was examined more closely. The mines consisted of
narrow vertical shafts that directly descended onto the top of the obsidian flow. More than 30 shafts
and shallow shaft depressions were observed at site 5, which covers an area approximately 1 ha in
size. No attempt was made to either map or record accurately all of the mines because of limited
time and the danger of falling into shafts partially covered by a thin veneer of humus, sticks, and
leaves. That hazard is the reason why local inhabitants avoid using the area for grazing or agriculture.
It is likely that there are more than 100 mine shafts in the area. Large piles of obsidian debitage
were identified immediately adjacent to the mines, where initial reduction was carried out. Local
informants reported a second, similar mining area on the top of Cerro El Coyote, near site 7 (Figure 2).
A lithic analysis by Sorensen (Sorenson and Hirth 1984:41) indicated that a wide variety oftools were
manufactured at or near the Los Hoyos source, including rough cores, bifaces, unifaces, and polyhedral blade cores. The waste materials located at sites 4 and 5 have the same characteristics as
workshops at El Chayal, Ixtepeque, and Otumba, where large waste piles include primary flakage,
abandoned percussion cores, and some broken bifaces and preforms (Coe and Flannery 1964). No
evidence for the production of finished tools was found at either the mines or the workshops.
The Giiinope Obsidian Source
The G
Giiinope obsidian source is located in the Honduran Department of Paraiso, near the town
of Giuinope, 35 km southeast of Tegucigalpa (Figure 1). To our knowledge the Giuinope source has
not been reported previously in the anthropological literature, and still remains to be surveyed in
a comprehensive manner. Dennis Coskren, of the El Cajon Archaeological Project, visited the area
in 1980, to investigate informal reports to the Instituto Hondureno de Antropologia e Historia that
an obsidian source might be located near Gilinope.
Obsidian samples were procured by Coskren from river gravels near the bridge that crosses over
the Quebrada Grande, 1.75 km west of the modern town. Obsidian was abundant along the floor
of the quebrada, occurring as exposed, water-worn cobbles ranging from 1 to 15 cm in diameter.
No attempt was made to locate the original source of the obsidian, but Coskren felt it probably was
to the south. Rough percussion flakes, small flake cores, and some debitage were identified along
the quebrada, but nothing that resembled a production workshop was encountered during this brief
visit.
Further survey during the summer of 1987 by Hirth established that the dispersed source for this
obsidian lies in the Cerro Grande area near Cerro Loma de Pie 3 km south of Coskren's original
collection area. While no obsidian outcrops were identified during the survey, obsidian cobbles
between 1 and 10 cm in diameter were noted in the soil matrix and in small quebradas over the 3
km2 area between locale 1 and the Cerro Loma de Pie (Figure 3). Local informants, interested in
exploiting the possible commercial potential of obsidian, report that no exposed in situ concentrated
outcrop exists anywhere in the Giinope region. Obsidian apparently occurs only as rock debris left
as erosional "float" from an ancient obsidian flow.
No conclusive evidence for prehistoric mining activities was found during the 1987 survey. No
evidence for vertical shaft mines similar to those at Los Hoyos near La Esperanza were observed
or reported by local informants. Rather, obsidian from the Giiinope zone apparently was collected
from colluvial and alluvial deposits from the Cerro Grande area. The outline of a trench approximately 15 m in length was observed at the base of Cerro Loma de Pie (locale 3). It exposed soils
with a high proportion of obsidian, including cobbles larger than those available on the surface.
Local informants were not aware of any historic or recent activity that could have resulted in that
trench. It is possible that the trench could be prehistoric, and that trenching was used to obtain
larger cobbles.
Lithic tools manufactured from obsidian were recovered sporadically throughout the survey area,
but not in quantities or types that would indicate specialized production. Tools included large and
148
AMERICANANTIQUITY
5ooooomE.
501
87000'
[Vol. 55, No. 1, 1990]
509
55'
Figure 3. Three collection locales in the Giiinope obsidian source, southeastern Honduras. Roads indicated;
grid squares are 1 km2.
small percussion flakes, percussion-flake cores, and unifacially retouched flake tools. No evidence
was recovered that indicated either prismatic-blade manufacture or bifacial manufacture. It is
important to note that the obsidian cobbles observed at Giiinope rarely exceeded 10 cm in diameter,
and therefore, obsidian-nodule size itself would not be an encouragement to core-blade technology.
While a variety of percussion-flake cores and tools could be produced from the majority of Giiinope
cobbles, most are too small to be transformed into percussion macrocores and then into polyhedral
cores for the pressure manufacture of prismatic blades.
Occurrence of Obsidian from the Giiinope and La Experanza Sources in
Central Honduran Archaeological Sites
Recent source analysis of obsidian from the El Caj6n region in central Honduras (Hirth 1985,
1988) has established that Giiinope and La Esperanza material composed a significant proportion
REPORTS
149
of the obsidian assemblage for all periods for which analyses were conducted (Late Formative-Late
Classic period). A total sample of 123 obsidian artifacts were analyzed using particle induced
X-ray emission analysis at Western Michigan University, under the supervision of Steve Ferguson.
Obsidian artifacts were analyzed for amounts of Sr, Rb, Zr, Mn, and Fe; provenience determinations
were made by plotting relative amounts of these elements on ternary diagrams (3-pole graphs), and
by then comparing them to source samples analyzed using the same technique.
Giiinope materials occur in low frequencies in Late Formative deposits at the site of Salitron
Viejo, where they constitute approximately 4 percent of the total sample (N = 28). The major
obsidian source utilized during the Late Formative appears to have been La Esperanza, which
constituted 70 percent of the analyzed collection.
Giiinope obsidian rises in frequency during the Early and Middle Classic periods. At Salitron
Viejo, Giiinope obsidian constitutes 12 percent of the collection (N = 34) while at the site of La
Ceiba it represents 36 percent of the analyzed sample (N = 69). While Giiinope obsidian continues
as an important source into the Late Classic, it occurs in slightly lower frequencies at the site of
Guarabuqui. Here Giiinope obsidian constitutes 5 percent of the analyzed Late Classic materials
(N = 20).
An important characteristic of the Giiinope obsidian used in these sites is that it only occurs as
simple flakes and percussion tools. All prismatic-blade manufacture was carried out on cores from
the La Esperanza, Ixtepeque, or El Chayal sources (Hirth 1988:Table 4). A complete analysis of the
lithic assemblage, being conducted by Jerrel Sorensen, indicates a higher frequency of prismatic
blades in the collection than would be expected by the number of exhausted obsidian cores. Polyhedral cores, core-rejuvenation artifacts, and core-shaping debitage are rare in project collections;
only one polyhedral core was recovered. It appears that trade for both finished blades and performed
cores was going on simultaneously throughout the El Cajon region. It appears that some prismaticblade manufacture was done in the El Cajon region, but the bulk of prismatic blades were manufactured outside the region, perhaps in the nearby Comayagua area.
Flakes and tools fashioned from Guiinope obsidian have a high frequency of unremoved exterior
cortex. It appears that much of the Giuinope obsidian was traded into the El Cajon region as small,
unworked cobbles that were reduced locally using simple percussion techniques. Flake tools also
were fashioned from small cobbles derived from the La Esperanza area. This closely parallels obsidian
tool manufacture at Quirigua, where the Classic Maya preferred core-blade technology on large
cobbles brought in from El Chayal, but other valley residents collected small obsidian nodules from
alluvial deposits and used exclusively percussion techniques to generate flake tools (Sheets 1983).
Obsidian flakes and percussion tools are much more abundant in central Honduras than in many
other areas of Mesoamerica, where prismatic blades are accessible more readily (Jerrel Sorensen,
personal communication 1988). Of the total sample of 80 percussion tools analyzed for source
provenience, 48 percent (N = 38) are from the La Esperanza source, and 38 percent (N = 30) are
from Giiinope. The quantity of Giiinope obsidian may even be higher than that reported here. An
unidentified source similar in several chemical characteristics to Giiinope accounts for approximately
14 percent (N = 12) of the percussion-tool assemblage; future reconnaissance might locate this flow
within the Giiinope source area.
Analytical Methods
In this study, 14 Nicaraguan and four Costa Rican samples were analyzed by X-ray fluorescence
(XRF) and neutron activation (NAA) at the Lawrence Berkeley Laboratory, University of California.
Procedural details, error estimates, and the composition of Standard Pottery are described in
Perlman and Asaro (1969, 1971). Additional details of the method are given in Stross et al. (1983).
The most significant elements measured by XRF generally are Ba, Rb, Sr, and Zr. Also measured
are Fe, Ce, Zn, Y, and Nb, and may be used in identification, especially if their abundances are
unusually high. Variations in sample size and shape introduce errors in the nondestructive XRF
procedure. Thin samples measured against thicker standards tend to yield values higher than the
true values. The use of abundance ratios of elements having nearly the same energy (e.g., Rb, Sr,
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AMERICANANTIQUITY
[Vol. 55, No. 1, 1990]
and Zr) largely cancels this error. The measurements are calibrated with El Chayal reference obsidian,
with abundances of Ba, Rb, Sr, and Zr taken as 915, 149, 153, and 117 ppm respectively (Asaro et
al. 1978; Stross et al. 1983).
The abundances (i.e., of Ba) or ratios (i.e., of Rb, Sr, and Zr) are calculated for the individual
samples. The mean values are calculated for each group having a common provenience assignment.
In addition, the standard deviations or root-mean-square deviations (RMSD) in these values are
calculated and compared with statistical errors inherent in counting radioactivity; this permits
evaluation of the performance of equipment and procedures.
If the RMSD of the critical elements in a group is less than 10 percent, and no sample has
abundances diverging by three standard deviations or more from the mean, all the artifacts probably
have the same provenience. If the RMSD for a provenience group is less than approximately 10
percent, and the group agrees to better than 10 percent with a reference group, it is assigned
provisionally to the reference group. A high-precision, destructive, "short" neutron activation analysis is then made of a representative member of the group. If the abundances of an artifact agree
within three standard deviations of the errors of measurements or of the RMSD of the NAA reference
group, the assignment of the artifact to the reference group is confirmed. The assignments of all the
artifacts in the provenience group also are considered confirmed.
Any artifact whose XRF composition does not conform to the criteria stated also is analyzed by
a short NAA, and if assignment still cannot be made, often by an "extended" NAA. If the composition
still does not match any of the sources known to us, it can at least be excluded positively from those
sources.
In a short NAA, the elements measured are Mn, Dy, Ba, Na, and K. In an extended measurement,
U, Ba, La, Ce, Sm, Eu, Yb, Co, Sc, Fe, Th, Cs, Rb, Hf, and Ta (as well as elements usually not
listed) are well determined in most obsidians. The uncertainties of the calibration standard, Standard
Pottery, are the major sources of systematic uncertainty after other systematic errors, believed
generally to be smaller than the counting errors, have been taken into account. Standard Pottery is
one of the very few standards in which the uncertainties are known for nearly all of the elements
that we measure.
Generally, if an obsidian artifact belongs to a well-defined group, the abundances in the artifacts
of the best-measured elements (usually 14-16 are taken) will deviate from those of the reference
group by no more than 2-3 percent on the average. Appreciably greater deviations normally are
taken to indicate a different source.
Analytical Results. Occurrence of Honduran and Guatemalan Sources of Obsidian in
Nicaraguan and Costa Rican Archaeological Sites
Of the 14 Nicaraguan obsidian specimens subjected to elemental analysis, nine were artifacts from
the site of Ninderi, and were donated for analysis by the Museo Tendiri. The other five obsidian
specimens from Nicaragua were source or possible source samples. Three of the four Costa Rican
samples analyzed during this study were artifacts, and one was not flaked clearly. The latter may
be a prehistorically transported source sample.
The nine Nicaraguan artifacts, all from the site of Ninderi, fell into two homogeneous groups.
Three of these artifacts, with the Berkeley catalog numbers NICA-9, -10, and -12, match the
Ixtepeque (Guatemala) source on the basis of X-ray fluorescence analysis (Table 1). All three are
prismatic blades, manufactured by the sophisticated mesoamerican core-blade system. This assignment for NICA-9 was confirmed by an "abbreviated" neutron activation analysis (Table 2). We
consider a confirmation by NAA of the provenience assignment for one member of a group defined
by XRF measurements as a confirmation of the entire group.
Ixtepeque is located north of Lake Guija, just inside Guatemala, a straight-line distance of 465
km. This confirms a direct connection with Mesoamerica, specifically with the Maya area. The
Museo Tendiri samples did not have any chronological context, but lithic technological evidence
indicates that the trade took place during the late Period V or early Period VI (periods from Lange
and Stone [1984:7]), relating to the mesoamerican Terminal Classic and Postclassic. The prismatic
REPORTS
151
Table 1. Elemental Abundances and Ratios of Obsidian Artifacts
from Ninderi, Nicaragua, by X-ray Fluorescence.
Ixtepeque Provenience
NICA-9
NICA-10
NICA-12
Mean
RMSD
Ixtepeque Referenceb
Abundance or Ratio
Error
Giiinope Provenience
NICA-6
NICA-7
NICA-8
NICA-11
NICA-13
NICA-14
Mean
RMSD
Giiinope Reference
Abundance or Ratio
Error
Baa (ppm)
Zra (ppm)
Rb/Zr
Sr/Zr
1,127
1,198
1,229
1,185
216
214
204
211
.53
.54
.50
.52
.02
.88
.87
.81
.85
.04
1,030
27
176
6
.57
.01
.90
.02
1,070
1,038
1,094
1,173
1,233
1,082
1,115
120
128
154
138
141
138
136
1.43
1.39
1.46
1.38
1.39
1.42
1.41
.03
1.61
1.64
1.72
1.60
1.65
1.69
1.65
.05
1,070
44
134
1.39
.09
1.53
.09
a The abundance levels of these elements
depend on the shapes and thickness
of the samples and are only approximate. The use of ratios (Rb/Zr and Sr/Zr)
of abundances largely compensates for these variations.
b
Stross et al. 1983.
blades collected by Lange and Sheets during the 1983 survey consistently came from later sites, and
when they had intact platforms, they were large, with minimal overhang removal, and highly pecked
and ground. Such platform-surface and edge preparation is characteristic of the last six centuries
prior to the Spanish Conquest.
The other six artifacts from Ninderi (three percussion
flakes and three prismatic blades) fell into
a group of matching compositions on the basis of XRF, which match the Giiinope source (Table
1). In order to obtain a better chemical description of the source, we completed our neturon activation
measurements on two of the samples (NICA-6 and NICA-8) and carried out an additional abbreviated NAA on another one (NICA-11)
(Table 3).
Table 2. Elemental Abundances of an Obsidian Artifact from
Ninderi, Nicaragua, and Guatemala Reference, by Abbreviated
NAA.
NICA-9 (Ninderi Artifact)
Al(%)
Ba (ppm)
Dy (ppm)
K(%)
Mn (ppm)
Na (%)
a See Asaro
b Error is
c Error is
7.15
1,041
2.43
3.60
454
3.13
?
+
?
+
+
.10b
36
.12
.29
9
.06
et al. 1978 and Stross et al. 1983.
typical counting error.
root-mean-square deviation.
Ixtepeque Referencea
7.24
1,030
2.30
3.61
449
3.05
+
+
+
?
+
?
.20c
27
.11
.26
9
.06
Table 3.
Elemental Abundances
NICA-8
NICA-6
Abundance
%A1
Ba
Ce
Co
Cs
Dy
Eu
%Fe
Hf
%K
La
Mn
% Na
Rb
Sb
Sc
Sm
Ta
Th
U
Yb
6.92
1,031
51.2
.51
8.02
2.53
.526
.878
3.31
3.59
28.4
520
2.73
181
.43
2.14
3.05
.873
12.00
3.99
1.79
of Obsidian Artifacts from Ninderi, Nicaragua; Rio Sapoa, Costa Rica;
Sources by NAA.
Error
Abundance
.08
7.03
1,010
50.0
.46
7.98
2.61
.504
.875
3.16
3.54
28.0
514
2.73
168
.30
2.12
3.04
.862
12.02
3.95
1.78
24
.5
.05
.11
.12
.009
.013
.06
.24
.5
10
.05
11
.07
.02
.03
.009
.12
.04
.03
NICA-11
Error
Abundance
.09
6.92
1,063
34
.9
.05
.12
.12
.009
.012
.06
.29
.5
10
.05
7
.05
.02
.03
.009
.12
.04
.04
Note: Elemental abundances in ppm except where otherwise indicated.
COST-2
Error
Abundance
Error
.12
38
2.56
.12
3.36
.28
518
2.69
10
.05
994
50.2
.53
7.91
2.40
.513
.872
3.26
3.71
27.2
510
2.71
163
.43
2.19
3.07
.899
12.08
3.96
1.81
45
.7
.07
.13
.12
.008
.012
.06
.26
.7
10
.05
6
.06
.02
.03
.009
.12
.04
.03
REPORTS
153
Table 4. ElementalAbundancesand Ratios of ObsidianPebbles
from Nicaragua,by XRF.
Baa (ppm)
Rb/Zr
Sr/Zr
191
256
.30
.26
1.31
.48
Zra (ppm)
NortheastShore Lake Nicaragua
NICA-1
NICA-2
1,629
1,848
Other pebbles (Luisitio)b
NICA-3
1,185
219
.23
2.5
NICA-4c
NICA-5
1,212
1,294
230
229
.4
.26
2.2
1.9
a The abundancelevels of these elements
dependon the shapesand thickness
of the samplesand are only approximate.The use of ratios(Rb/Zrand Sr/Zr)
of abundanceslargelycompensatesfor these variations.
b The three pebbles from Luisitio have similar unusualcompositions, with
iron abundancesat 6.5-8.5%,calcium -5-7%, titanium - 1.2%,and cerium
30 ppm. These pebblesare probablynot obsidianas their compositionsare
closer to that of basalt.
c The X-ray spectrumof NICA-4 used for the Rb, Sr, and Zr measurements
had a severe lead contamination,and these resultsare only approximate.
The five nonartifactual samples from Nicaragua appeared to be chemically different from one
another (Table 4) and from any other samples we had measured before. The two pebbles from the
northeast shore of Lake Nicaragua clearly are obsidian, but in situ sources for them are unknown.
Although the three pebbles from Luisitio visually look like obsidian, they have compositions different
from obsidian (Table 4). Although peralkaline obsidians could have greatly enhanced abundances
of iron and other elements, they also would be likely to have much higher Ce abundances than
measured. The observed compositions in NICA-3, -4, and -5 are closer to basalt than obsidian.
Luisitio should not be considered an obsidian source, until and unless further survey in the area
encounters obsidian. We found no evidence of prehistoric use of this material, while briefly visiting
the site and environs.
The two nodules found on the eastern shore of Lake Nicaragua may be from sources near there
(Table 4). Because these nodules were likely to be source samples, a detailed NAA study was
conducted (Table 5).
The two specimens of Nicaraguan nonartifactual obsidian (i.e., probable source) were found by
a Juigalpa resident along the northeast shore of Lake Nicaragua, in the "La Mesa" or "Puerto Diaz"
area, approximately 20 km northeast of Juigalpa. Chemically, these two nodules are sufficiently
different from each other, and from the three collected near Luisitio, to indicate that two different
sources may exist somewhere in central Nicaragua, perhaps near the north shore of Lake Nicaragua.
The diversity shown in these nonartifact samples illustrates the complexity of obsidian sources in
Central America, and the paucity of known sources which have been analyzed geochemically. Jaime
Incer (personal communication 1983) stated that he had encountered a natural deposit of obsidian
in a road cut along Highway 26, in the El Horno area about 40 km north of the north shore of Lake
Managua. He stated that all nodules were small, ranging from less than 1 to 6 cm in diameter. That
small size renders mesoamerican core-blade technology inapplicable. That source has yet to be
analyzed geochemically. A systematic survey for obsidian sources in western Nicaragua might locate
more sources.
After the Nicaraguan obsidian samples had been run, two obsidian samples from the Rio Sapoa/
Bay of Salinas area of northwest Costa Rica, and two others from the Vidor site on the Bay of
Culebra were analyzed. Distribution of obsidian in archaeological sites in the southern sector of
Greater Nicoya is limited almost exclusively to the Nicaraguan-Costa Rican border area. For
instance, out of 9,000 chipped-stone artifacts recovered by the Arenal Project, only two were of
obsidian, and both were so tiny and fragmental as to not be clearly artifactual.
[Vol. 55, No. 1, 1990]
AMERICANANTIQUITY
154
Table 5. ElementalAbundancesof ObsidianSamplesfrom the NortheastShore of Lake Nicaragua
and Artifactsfrom Costa Rica, by NAA.
NICA-2
NICA-1
Abundance
% A1
Ba
Ce
Co
Cs
Dy
Eu
% Fe
Hf
%K
La
Mn
% Na
Rb
Sb
Error
6.51
1,624
26.0
1.10
1.76
2.87
.739
1.080
4.35
2.54
12.3
640
3.27
62.9
.38
.15
40
.45
.06
.07
.14
.010
.012
.06
.33
.5
1.175
6.43
2.99
17.1
13
.06
2.7
.06
COST-1
Error
Abundance
Error
.5
.08
.12
.14
.015
1,837
39.2
.49
2.32
7.61
1.158
30
.07
.07
.08
.15
.016
.013
.08
.31
.6
1.204
6.36
3.61
17.1
.014
.09
.26
.4
6.15
1,873
39.9
.59
2.34
7.69
1.137
611
3.16
67.3
.79
.07
47
12
.06
3.0
.09
.06
3.7
.08
1.53
.03
.05
5.48
.06
1.50
.03
5.60
1.37
2.58
12
.02
.02
U
Yb
3.10
70.5
.55
.09
.06
.003
.05
.09
.06
.003
.04
.03
.03
.003
.03
591
9.34
6.43
.284
3.51
9.13
6.35
.280
3.50
3.24
2.71
.268
3.13
Sc
Sm
Ta
Th
Abundance
Note: In ppm except whereotherwiseindicated;errorsare the a uncertaintiesin countingX-rays.
The four Costa Rican obsidian samples were analyzed by XRF (Table 6). All were found to
correlate with obsidian sources or possible sources having compositions known to us, i.e., one with
Ixtepeque, one with Rio Pixcaya (Guatemala), one with Giiinope, and one with the possible source
near the northeast shore of Lake Nicaragua (collected by Sheets on the 1983 Nicaraguan survey).
Abbreviated NAA measurements were made on all Costa Rica samples (Table 7) and the NAA
analysis was completed for COST-1 (Table 5) and COST-2 (Table 3). The tentative match of COST-1
(Bay of Salinas) with the NICA-2 pebble from the northeast shore of Lake Nicaragua was confirmed.
The tentative match of COST-2 (Rio Sapoa Valley) with the chemical group represented by NICA6, -7, -8, -11, -13, and -14 was confirmed, and those artifacts are now attributed to the Giiinope
source. Ixtepeque (Guatemala) was confirmed as the source of COST-3 (Vidor site), and Rio Pixcaya
(Guatemala) as the source of COST-4 (Vidor site).
It is significant that the elemental analyses indicated that the two flake artifacts from Ninderi
came from Giiinope, 250 km to the northwest. This indicates a significant level of local working of
obsidian imported as a raw cobble from a considerable distance. These are primary working flakes,
rather than resharpening flakes. The cortex on them also is indicative of primary percussion technology. However, the flakes are too fragmentary to allow definite identification as part of a coreblade, household percussion flake, or other manufacturing system.
The analysis of the samples from northwest Costa Rica has interesting correlations with, and one
difference from, the Pacific Nicaraguan results. Both the prismatic-blade fragment (COST-3) and
the tool fragment (COST-4) were matched with Guatemalan source material, but the small northwestern Costa Rican suite includes a second Guatemalan source (Rio Pixcaya) that was not represented in the Nicaraguan collection, possibly indicating that an exchange system may have bypassed Nicaragua. However, the latter collection was also small, and the difference may well be due
to sampling. The source of the small primary waste flake from the Sapoa Valley (COST-2) is Giiinope,
which was well represented in the Nicaraguan artifacts.
The chronological contexts of the northwestern Costa Rican materials are all late Middle Poly-
REPORTS
155
Table 6. Elemental Abundances and Ratios of Obsidian Samples
from Costa Rica, by XRF.
Baa (ppm) Zra (ppm)
Lake Nicaragua Provenience
COST-1
Error
Reference Northeast Shore
Lake Nicaraguab
Error
Giiinope Provenience
COST-2
Error
Reference Giiinopec
Error
Ixtepeque Provenience
COST-3
Error
Reference Ixtepequed
Error
Rio Pixcaya Provenience
COST-4
Error
Reference Rio Pixcayad
Error
Rb/Zr
Sr/Zr
1,703
247
.27
.01
.48
.01
1,848
256
.26
.02
.48
.02
996
123
1,070
44
129
1.27
.03
1.38
.09
1.52
.03
1.55
.09
996
193
1,030
27
176
6
.54
.01
.57
.02
.88
.01
.90
.02
1,044
123
1,105
32
115
3
.94
.02
1.01
.05
1.59
.02
1.65
.06
a The abundance levels of these elements
depend on the shapes and thickness
of the samples and are only approximate. The use of ratios (Rb/Zr and Sr/Zr)
of abundances largely compensates for these variations.
b
See Table 4.
c See Table 1.
dSee Stross et al. 1983.
chrome/Late Polychrome period (1200-1520
A.D.), and this
placements assigned to the Nicaraguan specimens. This also
(Middle Polychrome) placement given by Healy (1980:285)
obsidian chips that he reported from Norweb's testing. Only
also correlates well with
correlated with the La
for "three and probably
one fragment of a blade
Table 7. Elemental Abundances of Obsidian Samples from Costa
Rica, by Abbreviated NAA.
Ba, ppm
Dy
(ppm)
K (%)
Mn
(ppm)
Na (%)
COST-3
Error
Reference Ixtepequea
Error
1,001
28
1,030
27
2.36
.07
2.30
.11
3.54
.16
3.61
.26
444
9
449
9
2.99
.06
3.05
.06
COST-4
Error
Reference Rio Pixcayab
Error
1,078
43
1,105
32
2.22
.11
2.03
.10
3.91
.26
3.54
.25
513
10
521
10
2.93
.06
2.94
.06
Note: See Tables 3 and 5 for COST-1 and COST-2 values.
See Asaro et al. 1978 and Stross et al. 1983.
bSee Stross et al. 1983.
a
the temporal
Virgen phase
four" of the
was reported
156
[Vol. 55, No. 1, 1990]
AMERICAN
ANTIQUITY
Table 8. Elemental Abundances of La Esperanza Honduras
Source Obsidian.
Abundance
% Al
Ba
Ce
Co
Cs
Dy
Eu
% Fe
Hf
%K
La
Mn
% Na
Rb
Sb
Sc
Sm
Ta
Th
U
Yb
By NAA
6.95
825
50.7
.86
4.52
2.36
.501
.897
4.14
3.75
28.9
427
2.84
163
.24
2.54
3.02
.959
11.7
3.53
1.62
Zr
Rb/Zr
Sr/Zr
By XRF
162
.90
.97
Error
.10
17
.6
.04
.05
.07
.006
.009
.05
.17
.4
9
.06
15
.14
.03
.03
.01
.1
.04
.03
.03
.02
Note: Values based on two samples, best values; ppm except where otherwise
indicated.
Table 9. Concordance.
Description
LBL Sample
NAA Pill
XRF
Provenience
Payson Sheets, nodule from northeast
shore Lake Nicaragua
Payson Sheets, nodule from northeast
shore Lake Nicaragua
Payson Sheets, Luisitio pebbles
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Payson Sheets, Ninderi artifact
Fred Lange, #101 Bay of Salinas
NICA-1
2208 J
8134-4
(possible source)
NICA-2
2208 K
8134-5
(possible source)
NICA-3,-4,-5
NICA-6
NICA-7
NICA-8
NICA-9
NICA-10
NICA- 11
NICA-12
NICA- 13
NICA-14
COST-1
2121 W
2147 M
8134-6, 7, 8
8134-9
8134-+
8134-8134-*
8134-1
8134-(
8134-$
8134-.
8134-]
8139-E
not obsidian
Giiinope
Giiinope
Giiinope
Ixtepeque
Ixtepeque
Giiinope
Ixtepeque
Giiinope
Giiinope
like NICA-2
Fred Lange, #86 Rio Sapoa Valley
COST-2
8139-F
Giiinope
Fred Lange, #3047 1-1-14 Vidor site
Fred Lange, #3047 I-1-3 Vidor site
Honduras source
Honduras source
COST-3
COST-4
LESP-5,-7
GUIN-1
8139-G
8139-H
8150-E, F
8150-G
Ixtepeque
Rio Pixcaya
La Esperanza
Giiinope
2161 T
2121 Y
2121 Z
2188
2218
2188
2207
2188
2215
2237
2237
J
2
K
W
M
Z
X, Y
Z
REPORTS
157
from the same excavations. The low frequency of obsidian reported by Healy is comparable to the
results obtained from the 1983 survey.
Although the La Esperanza source was not represented in the Nicaraguan or Costa Rican artifacts
under study, it is likely that unpublished or future analyses of obsidian from those countries will
encounter La Esperanza obsidian. Results of analyses made on the source samples from La Esperanza
secured by Hirth are shown in Table 8.
Table 9 is a concordance of the sample descriptions with the results of our analyses.
CONCLUSIONS
Considerable research has been conducted in Mesoamerica chemically fingerprinting sources of
obsidian and conducting elemental analyses to attribute obsidian artifacts found in archaeological
sites to their sources. The southern periphery of Mesoamerica, however, is not as well understood,
and the northern part of the Intermediate Area (central Honduras through northern Costa Rica)
has been a terra incognita in lithic sourcing. Fortunately, new information on two Honduran sources
of obsidian, and data on the use of those sources at sites in Honduras, Nicaragua, and Costa Rica,
are now available.
The La Esperanza source had been reported previously, but there had been some misunderstandings. La Esperanza apparently is a moderately large source, by mesoamerican standards, but a
systematic survey-and-testing program is needed. Nodule sizes are sufficient for core-blade technology, and evidence is clear that the mesoamerican system of macrocore shaping and prismaticblade manufacture was a major component of lithic manufacture at this source. The more informal
core-flake industry is yet to be documented at that source, and the chronology of exploitation of
the source is unknown, other than for Late Classic and Postclassic exploitation, which is reasonably
well demonstrated. Shaft-mining techniques and surface collection were used to obtain obsidian.
The Giuinope source was smaller, less exploited, and offered smaller nodules. The more informal
percussion core-flake industry predominated, but there seems to have been some core-blade exploitation, judging from the fact that some prismatic blades from the Ninderi site in Nicaragua are
attributed to Giinope by these analyses. The chronology of exploitation of this source is largely
unknown, with the exception of ample documentation of its use in the Postclassic period. The use
may have been associated with Pipil expansion into Salvador-Nicaragua.
The La Esperanza source appears to have been more mesoamerican, with major mining operations
and a predominance of core-blade technology. In contrast, Giiinope appears to have been used in
a fashion more common in the Intermediate Area, with no major mining operations, and a technology
dominated by the more informal percussion core-flake industry.
The various leads on small sources of obsidian in Nicaragua need to be investigated. Our data
indicate at least two sources remain to be pinpointed, and there may be more sources in adjoining
Honduras. As more sources are analyzed and as more artifacts can be attributed to sources in this
southern Mesoamerica-North ernIntermediate Area zone, the outlines of prehistoric trade, ethnic
interaction, and resource exploitation should be better understood.
Although we have attributed obsidian in Nicaraguan and Costa Rican archaeological sites to
sources as distant as Honduras and Guatemala, the conclusion that those sites were an integral part
of the mesoamerican mercantile system would be unwarranted. Rather, in prehistoric Nicaragua
and Costa Rica, the predominance of cutting edges were obtained by informal percussion removal
of small flakes from locally available nodules, probably with minimal occupational specialization
or centralization of economies.
Acknowledgments. The Nicaraguangovernment,and particularlyAnivel Martinez,are to be thanked for
hospitalityand assistancebeyond the call of duty duringthe Lange and Sheets visit of 1983. Honduranand
Costa Rican authoritieswere very helpful in the researchprogramsof Hirth, Lange,and Sheets. Brian McKee
critiqueda draft of this article and helped improve some initially opaque prose. Work reportedherein that
was performedat the LawrenceBerkeley Laboratoryat the University of Californiawas supportedby the
director,Officeof EnergyResearch,Officeof BasicEnergySciences,ChemicalSciencesDivision, U.S. Department
of EnergyunderContractNo. DE-AC03-76SF00098.
158
AMERICANANTIQUITY
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[Vol. 55, No. 1, 1990]
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